Analyte determination method and analyte meter
First Claim
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1. A method for determining an analyte in a sample comprising the steps of:
- (a) placing the sample in an electrochemical test cell comprising a working and a counter electrode and a mediator that serves as a charge carrier in the electrochemical determination of the analyte,(b) electrochemically determining an uncorrected result for the determination of analyte in the sample;
(c) determining an additive correction term for the amount of oxygen in the sample, and(d) modifying the uncorrected result of step (b) by adding the additive correction term of step (c) to provide a corrected determination of analyte in the sample,wherein the additive correction term for the amount of oxygen in the sample is determined as a function of the temperature of the sample and a measurement that reflects the oxygen carrying capacity of the sample,wherein the measurement that reflects the oxygen carrying capacity of the sample is determined applying a potential for a period of time sufficient to establish a chemical potential gradient between the electrodes, switching off the applied potential at a time tswitch, and obtaining a value indicative of the rate of decay of the chemical potential gradient in the absence of applied potential, andwherein the value indicative of the rate of decay is selected from the group consisting of;
a time tmob, which is determined by determining a time, tmeas, for a function of the slope of the decay of the potential to decay to a predetermined value, and wherein tmob=tmeas−
tswitch an instantaneous slope of the decay of potential; and
the change in potential over a predetermined time period after the potential is switched off.
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Abstract
The presence of oxygen or red blood cells in a sample applied to an electrochemical test strip that makes use of a reduced mediator is corrected for by an additive correction factor that is determined as a function of the temperature of the sample and a measurement that reflects the oxygen carrying capacity of the sample. The measured oxygen carrying capacity can also be used to determine hematocrit and to distinguish between blood samples and control solutions applied to a test strip.
28 Citations
6 Claims
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1. A method for determining an analyte in a sample comprising the steps of:
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(a) placing the sample in an electrochemical test cell comprising a working and a counter electrode and a mediator that serves as a charge carrier in the electrochemical determination of the analyte, (b) electrochemically determining an uncorrected result for the determination of analyte in the sample; (c) determining an additive correction term for the amount of oxygen in the sample, and (d) modifying the uncorrected result of step (b) by adding the additive correction term of step (c) to provide a corrected determination of analyte in the sample, wherein the additive correction term for the amount of oxygen in the sample is determined as a function of the temperature of the sample and a measurement that reflects the oxygen carrying capacity of the sample, wherein the measurement that reflects the oxygen carrying capacity of the sample is determined applying a potential for a period of time sufficient to establish a chemical potential gradient between the electrodes, switching off the applied potential at a time tswitch, and obtaining a value indicative of the rate of decay of the chemical potential gradient in the absence of applied potential, and wherein the value indicative of the rate of decay is selected from the group consisting of; a time tmob, which is determined by determining a time, tmeas, for a function of the slope of the decay of the potential to decay to a predetermined value, and wherein tmob=tmeas−
tswitchan instantaneous slope of the decay of potential; and the change in potential over a predetermined time period after the potential is switched off. - View Dependent Claims (2)
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3. A meter for receiving an electrochemical test strip having electrodes and providing a determination of an analyte in a sample applied to the electrochemical test strip when received in the meter, said meter comprising
(a) a housing having a slot for receiving an electrochemical test strip; -
(b) communications means for receiving input from and communicating a result to a user; and (c) means for determining an uncorrected result for the determination of analyte in the sample, determining an additive correction term for the amount of oxygen in the sample, and modifying the uncorrected result by adding the additive correction term of step (c) to provide a corrected determination of analyte in the sample, wherein the additive correction term for the amount of oxygen in the sample is determined as a function of the temperature of the sample and a measurement that reflects the oxygen carrying capacity of the sample, wherein the measurement that reflects the oxygen carrying capacity of the sample is determined by applying a potential for a period of time sufficient to establish a chemical potential gradient between the electrodes, switching off the applied potential at a time tswitch, and obtaining a value indicative of the rate of decay of the chemical potential gradient in the absence of applied potential, and wherein the value indicative of the rate of decay is selected from the group consisting of; a time tmob, which is determined by determining a time, tmeas, for a function of the slope of the decay of the potential to decay to a predetermined value, and wherein tmob=tmeas−
tswitch;an instantaneous slope of the decay of potential; and the change in potential over a predetermined time period after the potential is switched off. - View Dependent Claims (4, 5, 6)
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Specification